During fabrication of microelectronic devices, thin films and metal alloys are deposited on substrates and used as electrical conductors, adhesion layers and diffusion barriers. Ionized PVD has been utilized in semiconductor processing for metallization and interconnects, and promises to be useful to extend feature coverage performance up to submicron technology. IPVD often uses an inductively coupled plasma (ICP) for ionizing metal coating material. Chemical vapor deposition (CVD) and atomic layer deposition (ALD) also utilize metallic precursors to deposit metallic layers over structure, and also often use ICP to achieve ionization. ICP frequently is created by coupling energy from an external antenna through a dielectric window into a chamber. The RF transparent dielectric window must be protected from metallic deposits. Deposition baffles are used for this purpose. Such baffles must protect the window while maintaining RF transparency to energy from the antenna. Failure to protect the window can cause the window to fail.
For instance, the increased metal on the dielectric window will reduce the window's transparency to RF magnetic field from antenna, reduce RF power transfer into the plasma, and eventually, cause excessive heat within the deposited coating at the window. This will cause non-uniform heating of the dielectric window, inducing thermal stress in dielectric material that, in combination with mechanical stress, can cause the window to fail. In addition to hardware failure, RF power transferred into the plasma can decrease and reduce the efficiency of the plasma to ionize atoms. This loss of efficiency could result in changes of material properties deposited on the substrate, for example, deposition rate, feature coverage and uniformity. These changes are undesirable for process stability.
Therefore, enhanced performance of the deposition baffle to protect the dielectric window during the lifetime of deposition baffle is needed.